I haven't played a D-28 since I bought my D-35. I has a Piezo passive pickup and it's everything I need it to be, with Martin "Silk & Steel" strings!
I think the 3-piece back adds to the tone.
If I need something brighter, I'll play my Martin 0000-28H, which also has a passive pickup. Still plenty of base, but well balanced across the tonal spectrum.
Glen